1. Field of the Invention
The present invention relates to a process for preparing tetrazole-substituted anthranilamide derivatives of the formula (I)
by conversion of N-aryl- and N-hetaryl-substituted pyrazoles which contain methylenetetrazole radicals. The present invention further relates to the provision of a novel crystal polymorph of the corresponding anthranilamide derivatives by this process, and to the novel crystal polymorph and to the use thereof in agrochemical formulations.
2. Description of Related Art
The literature has already stated that, for example, the alkylation of alkyltetrazoles with, for example, alkyl iodides typically leads to a mixture of different regioisomers. In addition, the composition of the mixture depends strongly on the particular substituents on the tetrazole ring. For instance, William P. Norris, in J. Org. Chem., 1962, 27 (9), 3248-3251, states that the alkylation of 5-trifluoromethyltetrazole with methyl iodide gives rise to a mixture of the two regioisomers in a ratio of 6:1. The alkylation of alkyltetrazoles leads, in contrast, usually to 1-substituted tetrazoles (see R-A. Henry et al., JACS, 76, 923 (1954).
It is likewise known that the occurrence of active ingredients in different crystal polymorphs (polymorphism) is of great significance both for the development of preparation processes and for the development of formulations. For instance, the different crystal polymorphs of a chemical compound, in addition to appearance (crystal habit) and hardness, also differ in numerous further physicochemical properties. Differences with regard to stability, filterability, solubility, hygroscopicity, melting point, solid density and flowability can exert a strong influence on the quality and efficacy of crop treatment compositions. It has not been possible to date to forecast the occurrence and number of crystal polymorphs, including the physicochemical properties thereof. In particular, the thermodynamic stability and also the different behaviour after administration to living organisms cannot be determined in advance.